氯磺酚偶氮硫代若丹宁光度法测定微量金

研究了在CTMAB存在下,Au(Ⅲ)与氯磺酚偶氮硫代若丹宁的显色反应,实验表明,在pH = 3.0的盐酸溶液中,Au(Ⅲ)与试剂形成1:2的橘黄色络合物,其λmax = 460 nm,( = 1.52×105 L·mol-1·cm-1.Au(Ⅲ)含量在0～14 (g/10mL符合比尔定律.本法用于金矿石中微量金的测定,结果满意.     

新试剂N-烯丙基-N''-安替比林基硫脲光度法测定矿样中微量金

研究了新试剂N-烯丙基-N'-安替比林基硫脲与Au(Ⅲ)的显色反应.结果表明在pH=3.8～4.4的HAc-NaAc缓冲体系中,Au(Ⅲ)与该试剂形成1:2的络合物,其最大吸收峰位于275.0nm,表观摩尔吸光系数ε275.0=2.39×104L·mol-1·cm-1,Au(Ⅲ)含量在0～24.0μg/25mL内服从比尔定律.方法操作简便,选择性高.用于金矿石中微量金的测定,结果令人满意.     

新试剂N-烯丙基-N＇-安替比林基硫脲光度法测定矿样中微量金

研究了新试剂N-烯丙基-N'-安替比林基硫脲与Au(Ⅲ)的显色反应.结果表明在pH=3.8～4.4的HAc-NaAc缓冲体系中,Au(Ⅲ)与该试剂形成12的络合物,其最大吸收峰位于275.0nm,表观摩尔吸光系数ε275.0=2.39×104L·mol-1·cm-1,Au(Ⅲ)含量在0～24.0μg/25mL内服从比尔定律.方法操作简便,选择性高.用于金矿石中微量金的测定,结果令人满意.     

Au／TiO2催化剂的制备及低级醇类的光催化消除

采用沉积-沉淀法制备Au/TiO2催化剂,并用IR、TG-DTA、XRD、TEM、BET、FL、XPS、UV-vis DRS和PL等分析方法对其进行表征;测试和计算在甲醇的光催化消除反应中Au/TiO2催化剂的动力学参数;以低级醇类消除反应为模式反应评价催化剂在紫外光照下的光催化性能.结果表明:Au质量分数为1%的Au/TiO2催化剂在200 ℃下活化4 h的光催化活性最佳,0.15 g催化剂可将初始浓度为7.0 g/m3、流速为12.5 mL/min的甲醇和初始浓度为2.14 g/m3、流速为5 mL/min的乙醇以及初始浓度为2.21 g/m3、流速为4 mL/min的正丙醇完全消除;得到的反应活化能Ea = 14.80 kJ/mol,拟合的曲线线性关系好(R = 0.981 1),符合一级动力学反应规律.     

2-(2-喹啉偶氮)-1,3-二氨基苯光度法测定钯的研究

合成了新试剂2-(2-喹啉偶氮)-1,3-二氨基苯(QADAB),并研究了其与钯的显色反应,在0.2～3.0mol/LHClO4介质中,QADAB与钯反应生成2:1稳定络合物,体系λmax=590nm,ε=8.08×104L·mol-1·cm-1。钯含量在0.01～1.2mg/L内符合比尔定律。本方法用于一些含钯样品中钯含量的测定,结果令人满意。     

巯基树脂对金(Ⅲ)的吸附性能及其机理

研究了Au(Ⅲ)在巯基树脂上的吸附行为。结果表明:在298 K时静态饱和吸附容量为1106.9 mg/g树脂,用15%硫脲与1 mol.L-1盐酸的1∶1混合溶液作解吸剂解吸率可达92.60%。等温吸附遵循Freundlich经验式;测得在298 K时,吸附速率常数k298=5.23×10-5s-1;吸附活化能Ea=16.23 kJ.mol-1;吸附反应热效应ΔH=27.8 kJ.mol-1。用饱和容量法测定巯基树脂吸附Au(Ⅲ)的配位比均接近1∶1。红外光谱测定表明:树脂功能基-SH中硫原子与Au(Ⅲ)形成了配位键。     

Au/AC催化剂的制备及其催化性能

采用浸渍法制备改性活性炭负载金催化剂(Au/AC),并通过N2吸附-脱附、光电子能谱(XPS)对该催化剂进行表征,考察Au/AC催化剂在室温下对低浓度臭氧、甲苯以及二者共存时的催化分解性能.结果表明:Au/AC催化剂对臭氧具有优良的催化分解活性,在室温、空速76 000 h-1、相对湿度(45±5)%条件下,Au/AC对初始浓度为(55±5) mg/m3 的臭氧在2 300 min时的去除率为91.3%;Au/AC对甲苯的去除未表现出明显的催化分解性能,而是以吸附作用为主;在臭氧和甲苯共存的条件下,Au/AC对臭氧的催化分解活性显著降低;与臭氧反应后,Au/AC的表面石墨碳含量显著降低,说明臭氧能够通过Au/AC催化其与活性炭的反应得以降解,且在反应前后,活性组分Au能够保持稳定的单质价态.     

电流密度对无氰电镀Au凸点生长行为的影响

研究一种以氯金酸钠为主盐的无氰镀金液在80℃、镀液pH为8.0时阴极电流密度(J)对Au凸点生长行为的影响.结果表明:J在0.5～2.5A/din2范围内逐渐增大时,Au凸点牛长速度单调增大;当J=0.5～1.0A/dm2时,所得Au凸点晶粒细小、表面平整、内部敛密;当J=1.5～2.5A/dm2时,随着J的增大,凸点表面粗糙度逐渐增大,内部致密度逐渐降低;从凸点横截面形貌来看,在J=2.0A/dm2时出现树枝晶,在J=2.5A/dm2时树枝晶及晶间间隙已非常明显.确定了该镀液制作Au凸点的最佳电流密度为J=1.0A/dm2.此时,平均凸点厚度与施镀时间之间存在良好的线性关系.在蒸镀Au种子层并刻蚀有图形的si基板上得到外形规整且与基板结合良好的Au凸点.     

用电生的Fe(Ⅱ)-EDTA络合物在Fe(Ⅲ)-EDTA-ClCH2COOH-NaOAc缓冲溶液中精密库仑滴定金

提出了在Fe(Ⅲ)-EDTA—ClCH2COOH—NaOAc缓冲溶液中利用电生Fe(Ⅱ)-ED-TA络合物精密库仑滴定Au的方法。采用电位法检测终点，测定范围在5．2～17．0mg Au时，相对平均误差和标准偏差≤0．03％。方法可用于纯金、金合金和首饰等材料中Au含量的精密分析，选择性很好。讨论了电生Fe(Ⅱ)-EDTA络合物作库仑滴定剂的理论基础，获得了有益的结论。     

用DSPCF分光光度法测定钯

在室温下以硝酸为介质,钯与DSPCF形成有色络合物,其表观摩尔吸光系数ε_(520)=1.2×10~4,络合物组成为Pd(Ⅱ):DSPCF=1:2。其特点是在室温下发生显色反应,当加入HNO_3使介质达1.75N时,只有Pd(Ⅱ)—DSPCF红色络合物不褪色,可用于铂钯二次精矿等的测定。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.